1. Field of the Invention
The invention relates in general to a hinge apparatus, and in particular to a hinge apparatus utilizing magnetic components.
2. Description of the Related Art
Millions of people around the world use cellular phones. With such great gadgets, the owner can talk to anyone on the planet from just about anywhere. These days, cell phones provide an incredible array of functions, as well as a variety of the aesthetic appearances. The cell phones with or without their covers are generally sold in the commercial market, classifying the cell phones by appearance. Moreover, some models are designed as the folding type, in which the screen and the keypad are respectively on the folding part and the ground part. The cellular phone with cover is referred to as the “flip-type” phone from here on.
FIG. 1 is a perspective view of a flip-type cellular phone. The flip-type cellular phone 100 includes a phone body 120 and a flip cover 140, and a hinge apparatus connecting the two. The hinge apparatus, connecting the flip cover 140 and the phone body 120, allows the pivoting of the flip cover 140 on the phone body 120. The flip cover 140 is designed to protect the keypad from dust and careless touch. After the flip cover 140 is opened, the user can dial a number to make a call or receive/send an e-mail or message.
FIG. 2A is a drawing illustrating the motion of the flip cover of the cellular phone. With the special design, a critical angle exists in the rotation of the hinge apparatus 270. If the user desires to open the flip cover 140, the flip cover 140 will automatically rotate to the fully-opened position along the direction of B while the external force for opening the flip cover 140 disappears after the rotation angle is over the critical angle α. However, if the external force disappears before the rotation angle reaches the critical angle α, the flip cover 140 will automatically return to the fully-closed position along the direction of A. On the other hand, if the user wants to close the flip cover 140, it will automatically rotate to the fully-closed position along the direction of A while the external force for closing the flip cover 140 is removed after the rotation angle is smaller than the critical angle α. However, if the external force disappears before the rotation angle reaches the critical angle α, i.e., in the condition of the rotation angle greater than the critical angle α, the flip cover 140 will automatically return to the fully-opened position along the direction of B. Simply saying, the flip cover 140 is stably maintained at only two positions, as shown in FIG. 2B. Namely, the fully-closed flip cover 140 is maintained at the first stable equilibrium while the fully-opened flip cover 140 is maintained at the second stable equilibrium. The hinge apparatus 270 described above is adopted not only in the flip-type cellular phone, but also in the folding-type cellular phone.
This conventional hinge design, however, suffers from several drawbacks. After frequent usage, the conventional hinge, which typically uses a spring to provide the torsional force, will gradually lose the property of returning to the initial state following deformation, and the elastic force generated from the deformed spring is consequently decreased. Therefore, the issue of elasticity decay will shorten the utility life span of the hinge apparatus.